Slider For Slide Fasteners

Abstract

A slide fastener has an improved slider in which elbow members of each of the angulated flanges defining the slider channel have a chamfered inner edge whereby the slider exhibits improved operational smoothness, increased conformity to the configuration of the fastener under lateral loads and reduced fastener binding, cutting and wear.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to slide fasteners and, more particularly, to an improved slider for a filamentary fastener.

2. Description of the Prior Art

The acceptance of slide fasteners for a variety of diverse applications has been substantial and well recognized, and efforts to improve their appearance, ease of operation, resistance to binding, locking ability and overall quality continue to be made as new materials and manufacturing techniques are discovered.

By way of background, conventional slide fasteners typically include a pair of elongated carrier tapes upon which are attached a series of individual coupling elements along one of the longitudinal edges of each tape. Such elements have long been made of metal and are crimped or otherwise secured along a woven bead on the edge of each tape to form the fastener chain. A slider defining a V-shaped channel is slidably disposed on the chain and has a pull tab enabling one to selectively interengage or disengage the chain halves by upward or downward movement, respectively, of the slider.

With the advent of synthetic materials, such as nylon, considerable attention has been directed toward improving the construction of the carrier tapes per se as well as the interengageable coupling elements. As a result, slide fasteners employing continuous coiled or serpentine coupling elements formed from thin filaments of synthetic materials are now in widespread use and in a sense have revolutionized the fastener art. Such filamentary fasteners provide numerous advantages in many applications and are extremely economical to manufacture by reason of the simplicity with which the continuous formed filaments are constructed and sewn to the carrier tapes.

While many advances in the constrution of the coupling elements and the carrier tapes have been made in the past, the overall slider configuration has remained relatively unchanged from its initial design, with the exception of various lock modifications made specifically for synthetic fasteners. As a result of the unchanged slider construction modern filamentary fasteners often exhibit poor slider action characterized by binding, stiffness and excessive wear. Particularly susceptible to slider wear have been the exposed stitching threads used to attach the filamentary coupling elements to the carrier tapes since such threads were not present in the metal coupling link fasteners for which conventional sliders were designed and, thus, were not considered in the original design parameters. These threads are subject to excessive wear and fraying by the slider since the threads are forced against relatively sharp edges of the moving slider when the fastener is under lateral tension as when the fastener is being closed.

SUMMARY OF THE INVENTION

The present invention is summarized in that a slider for a slide fastener includes a main body member having a pair of spaced, parallel wing members, a pair of flanges extending respectively from opposite lateral edges of each wing member toward each other to define a Y-shaped channel for slidably receiving the slide fastener, and each of the flanges being chamfered along at least a portion of a longitudinal inner edge thereof whereby the channel conforms to the configuration of a laterally loaded fastener.

It is an object of the present invention to reduce operational effort of a fastener slider while improving overall fastener performance.

This invention has a further object in the construction of a fastener slider having fewer sharp edges and conforming to the configuration of a laterally loaded fastener chain.

Another object of the present invention is to reduce slider binding and excessive stitching thread wear while enhancing the smoothness of operation of a completed fastener.

Some of the advantages of the present invention reside in its freedom from binding, its smoothness in operation and its ability to provide improved operation without cutting, fraying or otherwise damaging or disrupting the fastener stitching threads.

Other objects and advantages of the present invention will become apparent from the following description of a preferred embodiment when taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a fragmentary plan view of a filamentary slide fastener having an improved slider according to the present invention;

FIG. 2 is an enlarged sectional view of the slider of FIG. 1;

FIG. 3 is a sectional view of a complete slider taken along line 3--3 of FIG. 2;

FIG. 4 is a sectional view similar to FIG. 3 taken along line 4--4 of FIG. 2;

FIG. 5 is a sectional view similar to FIG. 3 taken along line 5--5 of FIG. 2;

FIG. 6 is a sectional view of the fastener chain of FIG. 1 in an unloaded or relaxed state; and

FIG. 7 is a sectional view similar to FIG. 6 with the chain in a laterally loaded condition and showing the cooperation between the stitching threads and the slider according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is embodied in a filamentary slide fastener indicated generally at 10 in FIG. 1 including a pair of interengagable filamentary stringers 12 and 14 mounted on carrier tapes 16 and 18, respectively. The filamentary stringers 12 and 14 are each disposed along a longitudinal edge of a respective one of the carrier tapes at a woven, elongated bead 20-22 formed thereon and are held securely in place by any suitable means such as stitching threads 24 and 26, respectively, (FIG. 6). A pull tab 28 is connected to a slider, indicated generally at 30, which is disposed on tapes 16 and 18 to facilitate selective opening and closing of the slide fastener 10.

Slider 30 has a pair of parallel superposed wing members 32 and 34 which are joined at their upper ends (as visualized in FIGS. 1 and 2) by a generally rectangular spacing member or neck 36 having its longer dimension aligned longitudinally of the carrier tapes 16 and 18. As shown in the drawing, wing members 32 and 34 extend from neck or spacing member 36 in cantilever fashion. Spacing member 36 has an exterior end 38 which may be formed flush with the upper edges of wings 32 and 34 and an interior end 40 which is tapered in the plane of tapes 16 and 18 to form an apex 42. End 40 of spacing member 36 also may be tapered in a plane normal to the plane of tapes 16 and 18 to form a V-shaped edge (not shown) with the shaped edge and apex 42 joined by a smooth continuous surface which acts to separate the interengaged stringers 12 and 14 as the slider is moved downwardly along the fastener tapes.

Flanges 44 and 46, forming a first pair of opposing flanges, extend from one lateral edge of each wing member 32 and 34, respectively, toward each either; similarly, flanges 48 and 50, forming a second pair of opposing flanges, extend from an opposite lateral edge of each wing member 32 and 34, respectively, toward each other. Each of flanges 44, 46, 48 and 50 has a longitudinal portion 52-54-56-58 (shown in transverse section in FIG. 5) parallel to the longitudinal centerline of the slider 30 and an outwardly divergent portion 60-62-64-66 (shown in transverse section in FIG. 3) contiguously joined with the longitudinal portion to form an elbow 68-70-72-74 (shown in transverse section in FIG. 4). As shown in FIG. 2, each of the longitudinal and outwardly divergent portions is substantially straight such that each of the flanges 44, 46, 48 and 50 form an obtuse angle in the plane of the carrier tapes 16 and 18.

Angulated flanges 44, 46, 48 and 50, wing members 32 and 34, and tapered spacing member 36 cooperate to define a generally V-shaped channel for receiving the filamentary stringers 12 and 14 of the slide fastener 10. As shown in FIG. 2, each of the flanges 44, 46, 48 and 50 is disposed such that the elbow member thereof is adjacent the throat of the V-shaped channel and has a chamfered inner edge 76-78-80-82 to accommodate the configuration assumed by the fastener under a lateral load. Chamfered edges 76, 78, 80 and 82 are each in the form of a canted planar surface having a generally triangular periphery best seen in FIG. 2. The canted planar surfaces are obliquely disposed with respect to the longitudinal centerline of the slider 30 and to the parallel planes of wing members 32 and 34, with the angle of the canted surfaces less than the angle of the divergent portions of the flanges referenced to the slider longitudinal centerline.

The planar chamfered edges 76, 78, 80 and 82 of flanges 44, 46, 48 and 50, respectively specifically conform to the configuration of the synthetic fastener chain including tapes 16 and 18, filamentary stringers 12 and 14 and stitching threads 24 and 26 especially when the chain is subjected to lateral tension as normally experienced during closing of the fastener. This can be appreciated from FIGS. 6 and 7. In FIG. 6, a filamentary slide fastener is shown in section with the stitching threads illustrated in an unloaded or relaxed state. While the overall cross-sectional configuration of the stitching threads and the filamentary stringers is generally rectangular, it can be appreciated from a comparison with the diagrammatic view of FIG. 7, where the fastener is under a lateral load, that under the tension forces experienced in operation, the chain assumes more of an elongated hexagonal configuration. Thus, under tension, the tapes 16 and 18 tend to be drawn away from the filamentary stringers 12 and 14 causing the stitching threads to stretch and assume an oblique profile. Under these normally prevalent operating conditions, the canted planar surfaces 76, 78, 80 and 82 conformingly cooperate with the distorted stitching threads to promote smooth slider action and to obviate the thread wear so often caused by the relatively sharp-cornered flange edges heretofore used. As a result, the present construction reduces the operational effort required to open and close the fastener and assures smooth slider operation free from binding and stitching thread wear.

It is also noted the chamfered flange construction of the slider according to the present invention acts in a somewhat cam-like manner, especially during movement of the slider upward or in a closing direction, for enhancing the ability of the slider to draw the separated fastener chain halves together at the throat of the V-shaped channel. In other words, as the slider is moved upwardly, the fastener halves are forced together by the divergent portions of the slider flanges for intercoupling at the throat of the channel. The chamfered flange edges or canted planar surfaces 76, 78, 80 and 82 enable the fastener chain to pass through the channel without binding, as noted above, and at the same time act on the filamentary stringers 12 and 14 in a manner to promote the desired coupling thereof. Consequently, the slider 30 of the present invention does not tend to distort the filamentary stringers nor does it tend to pinch or capture individual stringer coupling elements as was often the case in the past.

Thus, the present invention provides a slider for a filamentary fastener having overall improved operational smoothness and freedom from binding, fraying and stitching thread wear. Furthermore, the slider of this invention conforms to the distorted configuration assumed by fastener chain made of synthetic materials and having modern filamentary coupling elements seron to the carrier tapes. As such, the present invention represents a substantial departure from the prior art in the specific inclusion of the characteristics of filamentary chain both at rest and under loading as slider design parameters.

Inasmuch as the present invention is subject to many variations, changes in details and reversal of components, it is intended that all matter contained in the foregoing description or shown on the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Claims

What is claimed is:

1. A slider for a slide fastener having filamentary coupling elements attached to a pair of carrier tapes by stitching threads, the slider comprising

a main body having a pair of spaced, parallel wing members and a longitudinal center line,

a pair of flanges extending respectively from opposite lateral edges of each of said pair of wing members toward each other to define a channel for slidably receiving said carrier tapes,

each of said flanges having a first portion substantially parallel to said center line,

each of said flanges having a second portion diverging outwardly from said center line,

each of said flanges having an elbow joining said first portion and said second portion, and

a single canted planar surface disposed on the inside of each of said flanges at said elbow and extending onto both of said first and second portions thereof, each of said canted planar surfaces forming a chamfer of said elbow and defining a plane obliquely angled with respect to said center line such that said canted planar surfaces permit slider movement without causing binding or wearing of the stitching threads.

2. A slider for a slide fastener as claimed in claim 1 wherein each of said outwardly divergent second portions of said flanges is angled away from said center line at an angle greater than that made by said canted planar surface with respect to said center line.